Calculator · Performance Lab
Sleep Calculator
Optimal bedtimes and wake-up times based on 90-minute sleep cycles.
Ergebnis
- 6 cycles · 9.0 h of sleep
- 21:45
- 5 cycles · 7.5 h of sleep
- 23:15
- 4 cycles · 6.0 h of sleep
- 00:45
Inside the ideal range (5–6 cycles).
Inside the ideal range (5–6 cycles).
Backup option — less than ideal.
Explained
What this calculator does for you
Sleep may be the single most important recovery lever — and the most underestimated. Bad sleep ruins training performance, hormone balance, appetite control and focus in hours, not weeks.
Sleep runs in cycles of about 90 minutes (light → deep → REM). Waking mid-cycle feels broken; waking at the end of a cycle feels fresh.
This calculator returns several sensible times — based on 4, 5 or 6 full cycles plus your fall-asleep duration. 5–6 cycles (7.5–9 h) are ideal for most adults.
Science
Scientific background
A full sleep cycle averages ~90 minutes — real values range from ~80 to ~110 and shift across the night.
NSF (National Sleep Foundation) recommends 7–9 hours/night for adults. Athletes often benefit from 8–10.
Regularity (same bedtime and wake time) is provably more important than 'perfect' end-of-cycle wake-ups.
Examples
Practical examples
Wake at 06:30, 15 min to fall asleep
Suggestions: 21:15 (6 cycles, 9 h) · 22:45 (5 cycles, 7.5 h) · 00:15 (4 cycles, 6 h). Ideal: 21:15 or 22:45.
Bed at 22:30, 15 min to fall asleep
Suggestions: 04:45 (4 cycles, 6 h) · 06:15 (5 cycles, 7.5 h) · 07:45 (6 cycles, 9 h). Ideal: 06:15 or 07:45.
Avoid these
Common mistakes
- 01Sacrificing sleep for training. Training is damaged more by bad sleep than gained from extra hours.
- 02Swinging bed and wake times between weekdays and weekends.
- 03Screens right up to bedtime. Blue light and stimulation push sleep onset later.
- 04Alarming awake mid-deep-sleep — feels worse than 30 minutes less sleep at a cycle boundary.
Recommendations
Further recommendations
- 01Hold a fixed sleep and wake rhythm — keep weekends close to it too.
- 02Dark, cool bedroom (~18 °C). Phone out of the bed.
- 03Don't train hard right before sleep. Last heavy meal 2–3 h prior.
- 04Avoid caffeine 6–8 h before bed — it lingers longer than most people think.
FAQ
Frequently asked questions
- Is the 90-minute cycle exact?
- No, an average. Real cycles run ~80–110 minutes and vary night to night. The calculator returns sensible guidelines.
- How much sleep do I really need?
- Adults 7–9 h. Athletes in hard phases more like 8–10 h. You notice it: waking without an alarm with a clear head = enough.
- Better to rise earlier or later?
- Regularity beats time-of-day. A constant rhythm 7 days a week beats a perfect plan 4 days a week.
- Can I 'catch up' on weekends?
- Helps a bit, but doesn't fully replace weekday deficit. Consistent good sleep is always more efficient than little + catch-up.
- What if I wake at night?
- Normal — happens to everyone. Only an issue if you're awake > 20 minutes. Then: get up, dim light, boring task, back to bed when sleepy.
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Knowledge Hub
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